Twenty years ago most criminologists and sociologists would have doubted that a metropolis could reduce this kind of crime by so much. Although the scale of New York Citys success is now well known and documented, most people may not realize that the city’s experience showed many of modern America’s dominant assumptions concerning crime to be flat wrong, including that lowering crime requires first tackling poverty, unemployment and drug use and that it requires throwing many people in jail or moving minorities out of city centers. Instead New York made giant strides toward solving its crime problem without major changes in its racial and ethnic profile; it did so without lowering poverty and unemployment more than other cities; and it did so without either winning its war on drugs or participating in the mass incarceration that has taken place throughout the rest of the nation.

The short answer is increased police presence and agressive street stops and arrests. But the longer answer is more complex because it involves shattering preconcieved ideas about crime prevention. For example, crime and drug use were not linked. Gentrification, it seems, has little to do with reducing rates, either. Even the policing strategies were new and counter to what you might expect:

Starting in 1994, the city also adopted a management and data-mapping system called CompStat. At a central office in downtown Manhattan, analysts compile data on serious crimes, including their exact locations, and map them to identify significant concentrations of crime. Patrols then deploy in full force on-site — whether it is a sidewalk, a bar or any other public place — sometimes for weeks at a time, systematically stopping and frisking anyone who looks suspicious and staring down everyone else. Although one might expect that criminals would just move to another street and resume their business as usual, that is not what happened in New York. Thus, crimes prevented one day at a particular location do not ineluctably have to be committed somewhere else the day after.

Of course, it’s hard to say what change has had the most effect on crime rates. The combination of multiple strategies could be answer (vs one singular act or change). But whatever the case, New York has had a significant reduction in crime relative to the rest of the nation given it’s population.